v1.8.0
https://github.com/libunwind/libunwind/commit/2c2566c79c4f9cb505e6a23e4ab884d856ef88fe

Apply https://github.com/libunwind/libunwind/pull/700
Apply https://github.com/libunwind/libunwind/pull/701
Apply https://github.com/libunwind/libunwind/pull/703
Apply https://github.com/libunwind/libunwind/pull/704
Revert https://github.com/libunwind/libunwind/pull/503 # issue: https://github.com/libunwind/libunwind/issues/702
Apply https://github.com/libunwind/libunwind/pull/714
Revert https://github.com/libunwind/libunwind/commit/ec03043244082b8f552881ba9fb790aa49c85468 and follow up changes in the same file # issue: https://github.com/libunwind/libunwind/issues/715
